Final answer:
When a client can complete less than 25% of an upper extremity dressing task, they require extensive assistance, which signifies that they need help for more than 75% of the task.
Step-by-step explanation:
In the context of occupational therapy and rehabilitation, when a client is only able to complete less than 25% of the task associated with dressing the upper extremities (UE), the level of assistance needed is considered to be extensive assistance. The various levels of assistance are categorized by the amount of effort or completion the client can provide during a task. If a client requires help for more than 75% of the task, extensive assistance is typically the appropriate level of support given. This classification helps in planning and documenting the progress of rehabilitation, ensuring that the assistance provided matches the individual needs of the client.